Paper pulp composition and article formed therefrom

ABSTRACT

A moldable paper pulp composition comprising an aqueous suspension of a base material comprising paper particles and a detergent resistant binding agent for the paper particles, in an intimate and substantially homogenous mix. Also provided are articles molded from the composition.

The present invention relates to paper pulp compositions and articlesmoulded therefrom.

It is known to form disposable urine bottles, bed pans and the like frompaper pulp which, after use, can be placed in a macerator to reduce theparticles to a size where they can be discharged into the normal sewersystem. It would also be desirable to form other articles, notably washbasins, from paper pulp so that they too are disposable. However, whilstthe moulding of wash bowls and the like presents few technical problems,it has been found that the presence of soap or detergent in the watercarried by the wash bowl renders the moulded paper pulp article veryabsorbent, with the consequence that the article disintegrates veryquickly, thereby rendering it unusable.

Therefore, for receptacles which are likely to come into contact withsoap or detergent, it is not possible to form them from disposable paperpulp and instead reusable receptacles, usually formed from plastics, areused. These require thorough cleansing after each use, but even withvery thorough cleaning, the risk of cross-contamination andcross-infection between patients remains.

It is an object of the present invention to provide a paper pulpformulation which can be made into moulded paper pulp articles whichwill allow the article to retain its shape and rigidity.

In accordance with a first aspect of the invention, there is provided amouldable paper pulp composition comprising an aqueous suspension of:

-   -   (a) a base material comprising paper particles; and    -   (b) a detergent resistant binding agent for the paper particles,        in an intimate and substantially homogenous mix.

By including a detergent resistant binding agent in the formulation, ithas been found that articles formed from the formulation do notdisintegrate when they come into contact with soap solution or detergentsolution. This makes the formulation particularly suitable for formingdisposable wash bowls, which are likely to come into contact with soapsolution or detergent solution in use. In addition, the compositionprovides the means for a cost effective process for the manufacture ofarticles capable of retaining their shape and rigidity since it is notnecessary to adapt conventional moulding techniques or machinery toprovide an article with the means to maintain its shape and rigidity.

The paper particles comprise a number of interwoven cellulose fibres.The detergent resistant binding agent is capable of binding the fibresof the paper particles together. The base material may further comprisean additional binder to improve the binding of paper fibres together.The binder may comprise a soluble wax. The soluble wax may be a natural(such as bee's wax) or synthetic (such as Alkyl Ketene Dimer (AKD) wax)wax. Preferably, the binder comprises a natural wax.

The composition may comprise 0-20% of binder by dry weight per Kg of drybase material, more preferably, 7-9%.

In one embodiment, the composition further comprises a sizing agent. Thesizing agent acts to improve the binding action of the binder and paperfibres and to lower the pH, improving the binding properties of thedetergent resistant binding agent and/or binder so as to enable themoulded, finished article to better retain its shape. The sizing agentmay be any suitable material capable of improving the binding of thedetergent resistant binding agent and/or binder and paper fibrestogether. Preferably, the sizing agent comprises an aluminium salt. Morepreferably, the sizing agent comprises aluminium sulphate.

The composition may comprise an additional 0-300 g of sizing agent bydry weight per Kg of dry base material, more preferably, 200-230 g.

The paper particles may be derived from any suitable material, forexample, in one embodiment the paper particles are derived from recyclednewspaper. The paper particles are advantageously derived from anyrecyclable source so as to minimise the environmental impact of themanufacturing process. The base material may comprise 65-100% by dryweight of paper particles, more preferably, 80-95%.

It has been found that by the addition of a detergent resistant bindingagent, the finished article is resistant to the effects of soap anddetergent solutions, with the effect that the finished article canwithstand such solutions while remaining intact.

It has been found that an amount from 10 ml to 200 ml of the detergentresistant binding agent per Kg of dry base material is effective toprovide the desired properties of resistance to soap and detergent. Anamount of 10 to 100 ml of detergent resistant binding agent per Kg ofdry base material is preferred, more preferably, 30-40 ml.

Preferably the amount of detergent resistant binding agent in terms ofsolids content is 1-100 g per Kg of dry base material, more preferably3-60 g, more preferably 3-30 g, more preferably 9-12 g.

The detergent resistant binding agent may comprise any material capableof providing sufficient detergent resistance to an article made from thecomposition so that the article can maintain its shape and rigidity evenwhen in contact with soap and detergent solutions. Preferably, thedetergent resistant binding agent comprises a fluorocarbon, morepreferably, a fluorocarbon resin emulsion, such as Mystolene D2404.

In one embodiment, the detergent resistant binding agent is MystoleneD2404 (available from Catomance technologies Limited, 4 Caxton Place,Stevenage, SG1 2UF, UK).

When formulating the composition, the detergent resistant binding agentmay advantageously be in the form of a resin, emulsion and/or resinemulsion. The detergent resistant binding agent acts to prevent themoulded article from disintegrating when in contact with soap anddetergent solutions.

The composition may additionally comprise at least one biocide toprevent the growth of micro-organisms prior to, during and after themanufacture of an article. The biocide may comprise any one or more ofthe following group, which comprises biozynol and bactolyse (availablefrom EKA Chemicals AB, Whiteberg Industrial Estate, Blackburn,Lancashire and Nalco Company, 1601 W. Diehl Road, Naperville, Ill.,60563-1198 U.S.A). In a preferred embodiment, the composition comprisesat least two different biocides.

The biocide is preferably present in an amount sufficient to arrest thegrowth of micro-organisms in the composition. More preferably, thecomposition comprises an additional 0-5 g of biocide per Kg of dry basematerial, even more preferably, 0.1-0.5 g.

In accordance with a second aspect of the present invention, there isprovided an article manufactured from a composition as describedhereinabove.

The articles manufactured using the composition of the present inventionare, in addition to being resistant to soap and detergent solutions,capable of maintaining their shape and rigidity when contacted withengine oil, cooking oil, emulsion paint and/or wall paper paste.

By way of example only, a specific embodiment of the present inventionwill now be described.

A receptacle in the form of an open-topped wash bowl comprises agenerally planar base and an upstanding peripheral enclosing wall,defining a containing volume. The wash bowl is formed from moulded paperpulp material in a known manner.

The relative proportions of the constituents of the paper pulp fromwhich the wash bowl is formed are as follows (the amounts given are forthe formation of 1 kg of dried paper pulp material):

915 g of particulate waste paper (e.g. old newspaper).

85 g of binder (e.g. wax, such as bees wax).

218 g of a sizing agent (such as aluminium sulphate).

35 ml of a detergent resistant binding agent (e.g. a fluorocarbon resinemulsion such as Mystolene).

Optionally, the mixture may also contain one or more biocide materials.

The above components of the composition are suspended in water such thatthe solid particles form from 0.8% to 1.5% of the aqueous suspension.The pulp material is then formed into wash bowls on conventional paperpulp moulding machines and the formed articles are then dried in an ovento form the finished article.

In alternative embodiments, the pulp material is formed into othervessels for containing or receiving engine oil, cooking oil, emulsionpaint and wall paper paste.

1. A moldable paper pulp composition comprising an aqueous suspensionof: (a) a base material comprising paper particles; and (b) a detergentresistant binding agent for the paper particles, in an intimate andsubstantially homogenous mix.
 2. A composition as claimed in claim 1,wherein the base material comprises a binder for binding the paperparticles.
 3. A composition as claimed in claim 2, wherein the bindercomprises a natural or synthetic wax.
 4. A composition as claimed inclaim 3, wherein the binder comprises a natural wax.
 5. A composition asclaimed in claim 2, wherein the base material comprises 0-20% of binderby dry weight per Kg of dry base material.
 6. A composition as claimedin claim 5, wherein the base material comprises 7-9% of binder by dryweight per Kg of dry base material.
 7. A composition as claimed in claim1, wherein the base material comprises 80-100% by dry weight of paperparticles.
 8. A composition as claimed in claim 1, wherein the detergentresistant binding agent comprises any material capable of providingsufficient water proofing and detergent resistance to an article madefrom the composition so that the article can maintain its shape andrigidity even when in contact with soap and detergent solutions.
 9. Acomposition as claimed in claim 8, wherein the detergent resistantbinding agent comprises a fluorocarbon.
 10. A composition as claimed inclaim 9, wherein the fluorocarbon is a fluorocarbon resin emulsion. 11.A composition as claimed in claim 1, wherein the detergent resistantbinding agent is present in an amount from 10 ml to 200 ml per Kg dryweight of base material.
 12. A composition as claimed in claim 11,wherein the detergent resistant binding agent is present in an amountfrom 10 ml to 100 ml per Kg dry weight of base material.
 13. Acomposition as claimed in claim 12, wherein the detergent resistantbinding agent is present in an amount from 30 ml to 40 ml per Kg dryweight of base material.
 14. A composition as claimed in claim 1,further comprising a sizing agent.
 15. A composition as claimed in claim14, wherein the sizing agent comprises an aluminum salt.
 16. Acomposition as claimed in claim 15, wherein the sizing agent comprisesaluminum sulphate.
 17. A composition as claimed in claim 14, wherein thecomposition comprises an additional 0-300 g of sizing agent by dryweight per Kg of dry base material.
 18. A composition as claimed inclaim 14, wherein the composition comprises an additional 200-230 g ofsizing agent by dry weight per Kg of dry base material.
 19. Acomposition as claimed in claim 1, further comprising at least onebiocide.
 20. A composition as claimed in claim 19, wherein the biocideis selected from the group consisting of biozynol and bactolyse andmixtures thereof.
 21. A composition as claimed in claim 19, wherein thecomposition comprises an additional 0-5 g of biocide per Kg of dry basematerial.
 22. A composition as claimed in claim 21, wherein thecomposition comprises an additional 0.1-0.5 g of biocide per Kg of drybase material.
 23. An article manufactured from a composition as claimedin claim
 1. 24. An article as claimed in claim 23, wherein the articleis a receptacle.
 25. An article as claimed in claim 24, wherein thereceptacle is an open-topped wash bowl.